Evaluation of Fuel Preparation Systems for Lean Premixing-Prevaporizing Combustors

1986 ◽  
Vol 108 (2) ◽  
pp. 391-395
Author(s):  
W. J. Dodds ◽  
E. E. Ekstedt
Keyword(s):  
System Design ◽  
Large Scale ◽  
Fuel Injection ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Fuel Injectors ◽  
Design Concepts ◽  
Mixture Preparation ◽  
Design Variables ◽  
System Length

A series of tests was conducted to provide data for the design of premixing-prevaporizing fuel-air mixture preparation systems for aircraft gas turbine engine combustors. Fifteen configurations of four different fuel-air mixture preparation system design concepts were evaluated to determine fuel-air mixture uniformity at the system exit over a range of conditions representative of cruise operation for a modern commercial turbofan engine. Operating conditions, including pressure, temperature, fuel-air ratio, and velocity had no clear effect on mixture uniformity in systems which used low-pressure fuel injectors. However, performance of systems using pressure atomizing fuel nozzles and large-scale mixing devices was shown to be sensitive to operating conditions. Variations in system design variables were also evaluated and correlated. Mixture uniformity improved with increased system length, pressure drop, and number of fuel injection points per unit area. A premixing system compatible with the combustor envelope of a typical combustion system and capable of providing mixture nonuniformity (standard deviation/mean) below 15% over a typical range of cruise operating conditions was demonstrated.

Numerical Investigation on Mixture Formation in a Turbocharged Port-Injection Natural Gas Engine Using Multiple Cycle Simulation

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Zhenkuo Wu ◽  
Zhiyu Han
Keyword(s):  
Fuel Injection ◽  
Load Condition ◽  
Operating Conditions ◽  
Injection Timing ◽  
Mixture Formation ◽  
Natural Gas Engine ◽  
Cycle Simulation ◽  
Mixture Preparation ◽  
Spark Timing ◽  
Multiple Cycle

In the present study, multidimensional computational fluid dynamics (CFD) simulations were carried out to study mixture formation in a turbocharged port-injection natural gas engine. In order to achieve robust simulation results, multiple cycle simulation was employed to remove the inaccuracies of initial conditions setting. First, the minimal number of simulation cycles required to obtain convergent cycle-to-cycle results was determined. Based on this, the in-cylinder mixture preparation for three typical operating conditions was studied. The effects of fuel injection timing and intake valve open scheme on the mixture formation were evaluated. The results demonstrated that three simulation cycles are needed to achieve convergence of the results for the present study. The analysis of the mixture preparation revealed that only in the initial phase of the intake stroke, there is an obvious difference between the three operating conditions. At the spark timing, for 5500 rpm, full load condition mixture composition throughout the cylinder is flammable, and for 2000 rpm, 2 bar operating condition part of the mixture is lean and nonflammable. The fuel injection timing has an insignificant impact on the mixture flammability at the spark timing. It was observed that the designed nonsynchronous intake valve open scheme has stronger swirl and x-direction tumble motion than the baseline case, leading to better mixture homogeneity and spatial distribution. With an increase in volumetric efficiency, particularly at 2000 rpm, full load condition, by 4.85% compared to the baseline, which is in line with experimental observation.

scholarly journals Superhybrid Composite Blade Impact Studies

1981 ◽  
Vol 103 (4) ◽  
pp. 731-738 ◽  
Author(s):  
C. C. Chamis ◽  
R. F. Lark ◽  
J. H. Sinclair
Keyword(s):  
Structural Integrity ◽  
Mechanical Design ◽  
Impact Resistance ◽  
Leading Edge ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Design Concepts ◽  
Composite Blade ◽  
Bird Impact ◽  
Small Bird

An investigation was conducted to determine the feasibility of superhybrid composite blades for meeting the mechanical design and impact resistance requirements of large fan blades for aircraft turbine engine applications. Two design concepts were evaluated: (1) leading edge spar (TiCom) and (2) center spar (TiCore), both with superhybrid composite shells. The investigation was both analytical and experimental. The results obtained show promise that superhybrid composites can be used to make light-weight, high-quality, large fan blades with good structural integrity. The blades tested successfully demonstrated their ability to meet steady-state operating conditions, overspeed, and small bird impact requirements.

Fuel Injection Scheme for a Compact Afterburner Without Flameholders

2007 ◽  
Author(s):  
Shai Birmaher ◽  
Philipp W. Zeller ◽  
Peter Wirfalt ◽  
Yedidia Neumeier ◽  
Ben T. Zinn
Keyword(s):  
Theoretical Model ◽  
Gas Turbine ◽  
Fuel Injection ◽  
State Of The Art ◽  
Combustion Process ◽  
Operating Conditions ◽  
Experimental Setup ◽  
Turbine Engine ◽  
Theoretical Predictions ◽  
Significant Length

State of the art afterburner combustion employs spray bars and flameholders in a long cavity, which adds significant length and weight to the engine and increases its observability. This paper presents a feasibility study for the development of a compact “prime and trigger” afterburner that eliminates the flameholders and reduces the length of the engine. In this concept, fuel is injected just upstream or in between the turbine stages in such a manner that upon exiting the turbine the fuel has evaporated and premixed with the flow without significant combustion, a process referred to as “priming”. Downstream of the turbine, combustion is initiated either through autoignition or by using a low power plasma radical generator being developed in a parallel investigation to “trigger” the combustion process. The prime and trigger injection and ignition scheme has been investigated using an experimental setup that simulates the operating conditions in a typical gas turbine engine. For this investigation, a trigger is not used, and combustion of the fuel occurs through autoignition. A physics-based theoretical model was developed to predict the location of autoignition for given flow and spray properties and injection locations. The theoretical predictions and the experimental results obtained using thermocouple measurements and CH* chemiluminescence confirm the feasibility of the prime and trigger concept by demonstrating the predictable and controlled autoignition of the afterburner fuel.

scholarly journals Thermal Energy Recovery from a Grid Connected Photovoltaic-Thermal (PVT) System Using Water as Working Fluid

2018 ◽  
Vol 7 (4.36) ◽  
pp. 389
Author(s):  
Alhassan Salami Tijani ◽  
Amer Farhan Bin Md Tahir ◽  
Jeeventh Kubenthiran ◽  
Baljit Singh Bhathal Singh
Keyword(s):  
System Design ◽  
Thermal Efficiency ◽  
Energy Recovery ◽  
Operating Conditions ◽  
Design Parameters ◽  
Working Fluid ◽  
Geometrical Configuration ◽  
Ansys Fluent ◽  
Design Concepts ◽  
Pressure Distributions

A Photovoltaic Thermal collector (PVT) is a combination of Photovoltaic (PV) and Thermal (T) collector. Many studies have tried to improve the electrical efficiency and thermal efficiency of this PVT system. The efficiency is influenced by many system design parameters and operating conditions such as the absorber temperature, velocity and pressure distributions. In this study, two new design concepts of absorber configuration of thermal collector have been investigated. This study also provides an important opportunity to advance the understanding of the effect of different geometrical configuration on the performance of the absorber.  Simulations were performed using ANSYS FLUENT 16.0 for both absorbers to determine the best absorber design that gives the highest thermal efficiency. Based on the simulations performed, perpendicular serpentine absorber proved to be the best design with the higher thermal efficiency of 56.45%.    

Effective Evaluation of Rotordynamic Performance Within Rotor-Bearing System Design Bounds

2021 ◽  
Author(s):  
Zhusan Luo ◽  
Carl L. Schwarz
Keyword(s):  
System Design ◽  
Operating Conditions ◽  
Performance Parameters ◽  
Critical Speeds ◽  
Effective Evaluation ◽  
Analytical Results ◽  
Design Variables ◽  
Rotor Bearing ◽  
Current Design ◽  
Bearing System

Abstract This paper presents a study on the effective evaluation of rotordynamic performance for multiple analysis cases within rotor-bearing system design bounds. The variations in rotordynamic design variables and operating conditions are usually considered in a rotordynamic analysis. This can provide useful information about the current design, potential for modification, and the capability of off-design operation. Typical design bounds of a tilting pad journal bearing are discussed to show the complexity of multiple design cases and a demand for a method to postprocess the analytical results. Rotordynamic performance is conventionally assessed by examining undamped critical speed maps, damped modes, stability, and unbalance responses. Evaluating rotordynamic performance for multiple cases is a tedious task for both rotordynamicists and reviewers. A new approach is studied to effectively extract, present and evaluate analytical results. A theoretical study shows the analytical results can be synthesized to determine key performance parameters. It is proposed that the amplification factors at critical speeds can be converted to equivalent logarithmic decrements. Based on the two studies, a new rotordynamic performance diagram is created to present damped modes, critical speeds and relevant acceptance criteria. With this informative diagram, one can quickly and effectively evaluate the acceptability and robustness of multiple design cases. This diagram can also convey the trends of key performance parameters, comparisons between cases, and the sensitivities of key performance parameters to design variables more clearly and concisely. This synthesizing approach and the rotordynamic performance diagram may be useful in modifying an existing design, determining a proper off-design operation range, and investigating rotordynamic issues.

scholarly journals Combustion Process of Canola Oil and n-Hexane Mixtures in Dynamic Diesel Engine Operating Conditions

2019 ◽  
Vol 10 (1) ◽  
pp. 80 ◽  
Author(s):  
Rafał Longwic ◽  
Przemysław Sander ◽  
Anna Zdziennicka ◽  
Katarzyna Szymczyk ◽  
Bronisław Jańczuk
Keyword(s):  
Surface Tension ◽  
Diesel Engine ◽  
Canola Oil ◽  
Storage Tank ◽  
Fuel Injection ◽  
Combustion Process ◽  
Operating Conditions ◽  
Preparation Process ◽  
Mixture Preparation ◽  
Dynamic Operating

The article discusses the problem of using canola oil and n-hexane mixtures in diesel engines with storage tank fuel injection systems (common rail). The tests results of the combustion process in the dynamic operating conditions of an engine powered by these mixtures are presented. On the basis of the conducted considerations, it was found that the addition of n-hexane to canola oil does not change its energy properties and significantly improves physicochemical properties such as the surface tension and viscosity. It contributes to the improvement of the flammable mixture preparation process and influences the course of the combustion process.

scholarly journals Analysis of Bifurcations in Multiharmonic Analysis of Nonlinear Forced Vibrations of Gas Turbine Engine Structures With Friction and Gaps

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
E. P. Petrov
Keyword(s):  
Gas Turbine ◽  
Large Scale ◽  
Parameter Variation ◽  
Forced Vibrations ◽  
Forced Response ◽  
Operating Conditions ◽  
Frequency Domain Method ◽  
Cubic Nonlinearity ◽  
Turbine Engine ◽  
Detection And Localization

An efficient frequency-domain method has been developed to analyze the forced response of large-scale nonlinear gas turbine structures with bifurcations. The method allows detection and localization of the design and operating conditions sets where bifurcations occur, calculation of tangents to the solution trajectory, and continuation of solutions under parameter variation for structures with bifurcations. The method is aimed at calculation of steady-state periodic solution, and multiharmonic representation of the variation of displacements in time is used. The possibility of bifurcations in realistic gas-turbine structures with friction contacts and with cubic nonlinearity has been shown.

Field-Testing of Biodiesel (B100) and Diesel-Fueled Vehicles: Part 4—Piston Rating, and Fuel Injection Equipment Issues

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Avinash Kumar Agarwal ◽  
Deepak Agarwal
Keyword(s):  
Pressure Drop ◽  
Large Scale ◽  
Fuel Injection ◽  
Field Trials ◽  
Operating Conditions ◽  
Experimental Results ◽  
Injection Equipment ◽  
Frictional Losses ◽  
Fuel Filter

Abstract This study investigated the use of biodiesel (B100) and baseline diesel in two identical unmodified vehicles to realistically assess different aspects of biodiesel's compatibility with modern common rail direct injection (CRDI) fuel injection equipment (FIE) and evaluate biodiesel's long-term durability/compatibility with engine components. Two identical vehicles were fueled with biodiesel (B100) and baseline mineral diesel for 30,000 km field-trials on highway under identical operating conditions. Exhaustive experimental results from this series of tests are divided into four segments. The fourth and the last paper of this series compares the effects of long-term usage of biodiesel on piston deposits and FIE components compared to baseline mineral diesel. A key challenge for improving engine performance and fuel economy is the reduction of frictional losses, primarily at the piston ring–liner interface, which accounts for majority of frictional losses. Piston rating was done for the two vehicles after the conclusion of field-trials and it revealed that rating of different piston sections was ∼5–15% superior in case of biodiesel-fueled vehicle compared to that of diesel-fueled vehicle. Performance of FIE components such as fuel filter, fuel injectors, and fuel pump was assessed after the conclusion of field-trials. Pressure drop at different fuel flow-rates across the fuel filter was measured for assessing the fuel filter blockage. Pressure drop across biodiesel filter was ∼30% higher than diesel filter after 10,000 km usage but almost twice after 15,000 km usage. These experimental results indicated that some additional technical measures should be taken by automotive manufacturers to offset these technical challenges before biodiesel is adapted on a large-scale in modern CRDI vehicles.

Development of Surface-Stabilized Fuel Injectors With Sub-Three PPM NOx Emissions

2002 ◽  
Author(s):  
Christopher K. Weakley ◽  
Steven J. Greenberg ◽  
Robert M. Kendall ◽  
Neil K. McDougald ◽  
Leonel O. Arellano
Keyword(s):  
Porous Metal ◽  
Operating Conditions ◽  
Stable Operation ◽  
Nox Emissions ◽  
Single Digit ◽  
Turbine Engine ◽  
Fuel Injectors ◽  
Developed Surface ◽  
Low Nox Emission ◽  
Full Pressure

ALZETA Corporation has developed surface-stabilized fuel injectors for use with lean premixed combustors which provide extended turndown and ultra-low NOx emission performance. These injectors use a patented technique to form interacting radiant and blue-flame zones immediately above a selectively-perforated porous metal surface. This allows stable operation at low reaction temperatures. This technology is a successful extension of ALZETA’s line of proven Pyromat™ SB metal fiber burners. A proof-of-concept injector in a full-pressure test rig at NETL in Morgantown, West Virginia achieved sub-3 ppm NOx emissions with concurrent single-digit CO emissions, both corrected to 15% O2. Operating conditions ranged between inlet pressures of 182.4 kPa (1.8 atm) and 1236.2 kPa (12.2 atm), inlet temperatures between 86° C (186° F) and 455° C (850° F) and calculated adiabatic flame temperatures between 1466° C (2670° F) and 1593° C (2900° F). Testing with prototype fuel injectors in test rigs at Solar Turbines last year yielded similar results. In May of 2001, a Solar Saturn 1 MW gas-turbine engine was operated to 95% load with a surface-stabilized injector. Programs are moving forward to adapt these injectors to the Solar Turbines Taurus 60 and Titan 130 engines. Engine tests are scheduled to begin in 2003.

RBF-trained POD-accelerated CFD analysis of wind loads on PV systems

2017 ◽  
Vol 27 (3) ◽  
pp. 660-673 ◽  
Author(s):  
Victor Huayamave ◽  
Andres Ceballos ◽  
Carolina Barriento ◽  
Hubert Seigneur ◽  
Stephen Barkaszi ◽  
...  
Keyword(s):  
Real Time ◽  
Large Scale ◽  
Operating Conditions ◽  
Time Response ◽  
Cfd Analysis ◽  
Pv System ◽  
Data Set ◽  
Content Type ◽  
Pv Systems ◽  
Design Variables

Purpose Wind loading calculations are currently performed according to the ASCE 7 standard. Values in this standard were estimated from simplified models that do not necessarily take into account relevant flow characteristics. Thus, the standard does not have provisions to handle the majority of rooftop photovoltaic (PV) systems. Accurate solutions for this problem can be produced using a full-fledged three-dimensional computational fluid dynamics (CFD) analysis. Unfortunately, CFD requires enormous computation times, and its use would be unsuitable for this application which requires real-time solutions. To this end, a real-time response framework based on the proper orthogonal decomposition (POD) method is proposed. Design/methodology/approach A real-time response framework based on the POD method was used. This framework used beforehand and off-line CFD solutions from an extensive data set developed using a predefined design space. Solutions were organized to form the basis snapshots of a POD matrix. The interpolation network using a radial-basis function (RBF) was used to predict the solution from the POD method given a set of values of the design variables. The results presented assume varying design variables for wind speed and direction on typical PV roof installations. Findings The trained POD–RBF interpolation network was tested and validated by performing the fast-algebraic interpolation to obtain the pressure distribution on the PV system surface and they were compared to actual grid-converged fully turbulent 3D CFD solutions at the specified values of the design variables. The POD network was validated and proved that large-scale CFD problems can be parametrized and simplified by using this framework. Originality/value The solar power industry, engineering design firms and the society as a whole could realize significant savings with the availability of a real-time in situ wind-load calculator that can prove essential for plug-and-play installation of PV systems. Additionally, this technology allows for automated parametric design optimization to arrive at the best fit for a set of given operating conditions. All these tasks are currently prohibited because of the massive computational resources and time required to address large-scale CFD analysis problems, all made possible by a simple but robust technology that can yield massive savings for the solar industry.

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